這一章我們來學習Android中的XML解析器,Android中自帶瞭三個XML解析器,有PULL,SAX,DOM解析器,其中PULL跟SAX都是以事件作為驅動導向的解析器,優點是占用內存小,處理速度快,DOM是將整個XML放入內存中再解析,處理速度要稍差一些,但DOM也有自己的優點,可以在解析的時候適當增加節點.OK,我們先來看一下我們要解析的xml文件
<?xml version="1.0" encoding="UTF-8"?>
<persons>
<person id = "1">
<status>大徙弟</status>
<name>孫悟空</name>
<tool>金箍棒</tool>
<number>殺死瞭50隻妖怪</number>
</person>
<person id = "2">
<status>二徙弟</status>
<name>豬八戒</name>
<tool>九齒釘耙</tool>
<number>殺死瞭40隻妖怪</number>
</person>
<person id = "3">
<status>三徙弟</status>
<name>沙和尚</name>
<tool>降妖寶杖</tool>
<number>殺死瞭30隻妖怪</number>
</person>
</persons>
這裡面定義瞭一些個人的信息和其他具體信息,好瞭,存入模擬器的SD目錄下,接下來,我們先定義JavaBean,Person.java
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public class Person
{
private String id;
private String status;
private String name;
private String tool;
private String number;
public String getId()
{
return id;
}
public void setId(String id)
{
this.id = id;
}
public String getStatus()
{
return status;
}
public void setStatus(String status)
{
this.status = status;
}
public String getName()
{
return name;
}
public void setName(String name)
{
this.name = name;
}
public String getTool()
{
return tool;
}
public void setTool(String tool)
{
this.tool = tool;
}
public String getNumber()
{
return number;
}
public void setNumber(String number)
{
this.number = number;
}
@Override
public String toString()
{
return "Person [id=" + id + ", status=" + status + ", name=" + name
+ ", tool=" + tool + ", number=" + number + "]";
}
}
對應上面xml的文件中的數據,接下來就是重點嘍,要好好學哦,呵呵,PULL解析類PullHandler.java
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import org.xmlpull.v1.XmlPullParser;
import android.util.Xml;
public class PullHandler
{
private InputStream input;
private List<Person> persons;
private Person person;
public PullHandler()
{
}
public void setInput(InputStream input)
{
this.input = input;
}
public PullHandler(InputStream input)
{
this.input = input;
}
public List<Person> getPersons()
{
try
{
XmlPullParser parser = Xml.newPullParser();
parser.setInput(input, "UTF-8");
int eventType = parser.getEventType();
while (eventType != XmlPullParser.END_DOCUMENT)
{
switch (eventType)
{
//XmlPullParser.START_DOCUMENT表示開始文檔事件
case XmlPullParser.START_DOCUMENT:
persons = new ArrayList<Person>();
break;
// XmlPullParser.START_TAG: 開始標簽
case XmlPullParser.START_TAG:
//parser.getName()獲取節點的名稱
String tag = parser.getName();
if ("person".equals(tag))
{
person = new Person();
//parser.getAttributeName(0)取得<person id="1">中的第一個屬性值
String id = parser.getAttributeValue(0);
person.setId(id);
}
if (null != person)
{
if ("status".equals(tag))
{
//parser.nextText();獲取下一個text類型的節點
person.setStatus(parser.nextText());
}
if ("name".equals(tag))
{
person.setName(parser.nextText());
}
if ("tool".equals(tag))
{
person.setTool(parser.nextText());
}
if ("number".equals(tag))
{
person.setNumber(parser.nextText());
}
}
break;
// XmlPullParser.END_TAG:結束標簽
case XmlPullParser.END_TAG:
if ("person".equals(parser.getName()))
{
persons.add(person);
person = null;
}
break;
}
//event=parser.next();繼續下一個元素
eventType = parser.next();
}
input.close();
return persons;
} catch (Exception e)
{
e.printStackTrace();
}
return null;
}
}
OK,解析類寫完瞭,測試一下吧,用上一節課的單元測試試一下呢,對於每個小方法做單元測試很重要,這要能及時解決出現的問題,呵呵,我快像唐僧一樣瞭,阿彌陀佛,要是不明日章元測試的話,就看一下
Android[中級教程]第四章 單元測試AndroidTestCase
import java.io.File;
import java.io.FileInputStream;
import java.util.List;
import android.os.Environment;
import android.test.AndroidTestCase;
public class PullHandlerTest extends AndroidTestCase
{
public void testGetPersons(){
//取得當前SD目錄下的文件路徑
File SD_Files = Environment.getExternalStorageDirectory();
//取得persons.xml文件的路徑,這裡我是存在sdcard/persons.xml
String file_path = SD_Files.getName() + File.separator + "persons.xml";
try
{
FileInputStream fis = new FileInputStream(new File(file_path));
PullHandler pullHandler = new PullHandler(fis);
List<Person> persons = pullHandler.getPersons();
//輸出persons中的數據
System.out.println(persons);
} catch (Exception e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
測試類寫完瞭,測試一下吧,OK,接下來就是定義main.xml瞭
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView android:textAppearance="?android:attr/textAppearanceMedium"
android:layout_width="wrap_content" android:text="唐僧的三個徙弟"
android:layout_height="wrap_content" android:id="@+id/textView1"
android:paddingLeft="10dip" android:paddingBottom="10dip"></TextView>
<ListView android:id="@+id/xml_list" android:layout_height="wrap_content"
android:layout_width="match_parent"></ListView>
</LinearLayout>
定義瞭一個ListView和一個TextView,ListView是準備顯示xml中的數據的
再定義一個list_item.xml是每一行要顯示數據的樣式
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout android:layout_height="wrap_content"
android:id="@+id/linearLayout1" android:layout_width="match_parent">
<TextView android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:layout_width="wrap_content" android:text="ID: "
android:paddingLeft="10dp"></TextView>
<TextView android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:layout_width="wrap_content" android:text="TextView"
android:id="@+id/id"></TextView>
<TextView android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:layout_width="wrap_content" android:text="TextView"
android:id="@+id/name" android:paddingLeft="30dp"></TextView>
</LinearLayout>
<LinearLayout android:layout_height="wrap_content"
android:id="@+id/linearLayout2" android:layout_width="match_parent">
<TextView android:layout_height="wrap_content"
android:layout_width="wrap_content" android:text="殺死瞭"
android:paddingLeft="10dp"></TextView>
<TextView android:text="TextView" android:id="@+id/number"
android:layout_width="wrap_content" android:layout_height="wrap_content"
android:textColor="#FF0000"></TextView>
<TextView android:text="隻妖怪" android:layout_width="wrap_content"
android:layout_height="wrap_content"></TextView>
</LinearLayout>
</LinearLayout>
好瞭,都定義完瞭,最後就是我們的Activity瞭
</pre><pre class="java" name="code">import java.io.File;
import java.io.FileInputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.widget.ListView;
import android.widget.SimpleAdapter;
public class PullActivity extends Activity
{
private ListView listView;
private SimpleAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState)
{
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.xml_handler);
listView = (ListView)findViewById(R.id.xml_list);
try
{
//自完義適配方法
getAdapter();
} catch (Exception e)
{
e.printStackTrace();
}
listView.setAdapter(adapter);
}
//自定義適配方法
private void getAdapter() throws Exception
{
List<Map<String, String>> lists = new ArrayList<Map<String, String>>();
//這一部分就是剛才我們做測試用的部分
File SD_Files = Environment.getExternalStorageDirectory();
String file_path = SD_Files.getName() + File.separator + "persons.xml";
FileInputStream input = new FileInputStream(new File(file_path));
PullHandler pullHandler = new PullHandler(input);
List<Person> persons = pullHandler.getPersons();
//將persons中的數據轉換到ArrayList<Map<String, String>>中,因為SimpleAdapter要用這個類型的數據進行適配
Map<String, String> map;
for(Person p : persons){
map = new HashMap<String, String>();
map.put("id", p.getId());
map.put("status", p.getStatus());
map.put("name", p.getName());
map.put("tool", p.getTool());
map.put("number", p.getNumber());
lists.add(map);
}
//HashMap<String, String>中的key
String[] from = {"id", "status", "name", "tool", "number"};
//list_item.xml中對應的控件ID
int[] to = {R.id.item_id, R.id.item_status, R.id.item_name, R.id.item_tool, R.id.item_number};
adapter = new SimpleAdapter(this, lists, R.layout.handler_list_item, from, to);
}
}
好瞭,最後就是上圖瞭
摘自:kangkangz4的專欄